A driving assistance method and driving assistance device are known (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2008-265719) that, even if a blind spot is caused by a pillar when a driver is looking past a mirror at a vehicle's surroundings, may display an image of a blind spot region Ad at the pillar. This technology is constituted such that, in order to suppress warping of the image projected at the pillar, an image corrected by image processing is outputted to a projector.